Effects of system parameters on the bifurcations of a flexible rotor response in squeeze-film dampers without centering springs

Abstract

The effects of the design and operating parameters, namely the bearing parameter (B), gravity parameter (W) and mass ratio (α), on the bifurcations in the response of a flexible rotor supported by squeeze-film dampers without centering springs were examined using direct numerical integration. Specifically, the effects of these parameters on the onset speed of bifurcation and the extent of non-synchronous response within the range of speed parameter (Ω) between 0.5 and 5.0 were determined. The results showed that increasing B resulted in the increase of the onset speed of bifurcation, and a decrease in the range of Ω where non-synchronous response was observed. With the exception of the case of W=0.0, the increase of W was found to increase the onset speed of bifurcation and also the range of Q where non-synchronous response was observed. The effect of increasing a resulted in a decrease in the range of Ω where non-synchronous response existed. The increase of a also caused the onset speed of bifurcation to increase, except for the case of B =0.05, W =0.0, where the onset speed of bifurcation was observed to decrease as α was increased. The numerical results presented in this work were obtained for an unbalance parameter (U) of 0.1, which is considered to be at the upper end of the acceptable range of balance quality specifications for practical rotor systems.